Control of duplex pneumatic sewage ejectors



NOV- 14, 1944. E. J. CIABA-r'rARl j 2,362,802

CONTROL OF DUPLEX PNEUMATIC SEWAGE EJECTORS Filed April 16, 1943 arrangement.

y Patented Nov. 14, 1944 UNITED STATES e j I 21,362,802

PATENT oFFicE CONTROL 0F DUPLEX PNEUMATIC SEWAGE EJECTORS Emil J. Ciabattari, Chicago, Ill.,` assignor to `Yeomans Brothers Company, a corporation of Delaware Application April 1s, 1943, serial No. 483,272

comms. ,ict 10a-246i) u This invention relates to the control of the discharging operation of an installation comprising two or duplex pneumatic sewage receivers` or socalled ejectors. f

The main object of the invention is to` provide :c

an arrangement lto prevent simultaneous discharge or ejection of sewage from both of the receivers, and especially to 'provide a pneumatically controlled arrangement for this purpose.

It is more or less common practice in large buildings and in industrial plants and in municipal Asewage systems to provide two substantially like sewage 'receivingl receptacles connectedV so` as to be capable'of simultaneously receiving sewage from a common source. Each of the receivers is preferably provided with an independent outlet connection to ahigh level sewervpipe which conducts the sewage to a` main'sewer pipe or to settling tanks in a treatment plant. Duplex units are employed in preference to a single unit having a capacity equal tothe total'capacity of the' duplex units for the reason that the'use of duplex units permits operation tov discharge a smaller volume 'of sewage at a more nearly-constant rate than is -possible where a single large capacity vreceiver is employedand which must be intermittently emptied,. usually by a 'high volume discharge flow. Considerations rof interna1 friction' in the outlet piping 'and also, in the case rvof discharging of sewage into settling tanks, consideration of agitation make the duplex `unit arrangement advisable. Other reasons also exit'for preferring a duplex arrangement to' a single large capacity In the case of duplex pneumatic ejectors, 'in which an air compressor motor is-started and stopped directly from electrodes in the respective receivers', simultaneous discharge of the* two re'- ceivers has been eilectively accomplished by ernploying an electrical interlock between the motor! starting equipment so that when one motor is running, the other cannot start.' Thisarrangeduplex sewage ejectors, and which mechanism is especially adapted, although not necessarily restricted, to` employment in connection with-systems in which the compressed air supply is derived from a stored compressed air source.

Other lobjects and advantages of the invention will be understood by reference to the following `specification and accompanying drawing, wherein there is moreor less diagrammatically illustrated in the single gure, aselectedembodiment ofl the invention.

In the drawinggialpa'ir of sewage receivers Il'and 2 are represented as having their inlet conduits 13 and drrespectively connected to a common conduit 35. lInthe diagrammatic illustration, the connection to the conduit orI pipe 35 is illustrated in such a location that there will'be a tendency for the'sewageto flow equally to the two receivers. This, however, is not essential, although it isadvantageous in instances where approximatev alternate operation ordi'scharge of the receivers is desired. The receivers I and /2 have outlet conduits 5 and 6 respectively which, it will be underst0od, are usually connected to a common discharge or so-called'force pipe which ordinarily carries the sewage to a higher level and to ar main sewer or to a settling tank. I

ment is not, however, adaptableto the centrol of duplex units which receive their compressed air supply `from a compressed air storage tank or other airvsupply system Ain which they compressor motors may not be startediand stopped.` l

As indicated, the present invention has todo particularly with the control of duplex pneumatic sewage ejectors. in which compressed`r air is supplied froma 4'storage tank or' similar source of stored compressed air. v

It is a further object of theinventionto provide eicient, simple, durable and reliable mechanism forpreventing the simultaneous discharge of The receivers'l and 2.' are connected by means of conduits 1 and 8 respectively, through threeway valves Sand IILfto conduits II-and'-I2, whichv arek in turn connected to a source of compressed air.' The {three-way valves Stand I0 also have `connections lI3 and I4 respectively to the atmospl'iere.` f

The valves 9 and IU are preferably in the form of piston 'valves which may be pneumatically adjusted so that in one position of the piston, the conduits. 1- and 8` are connected to the corn'- pressed air supply through the conduits II and VI2; In the other position of the pistons of the valves, the conduits 'I and 8 are'connected to the relief or exhaust connections 3 and I4. It will be understood, of course, that the three-way valves-9 and Ill are such that there is no direct connection between the air inlet pipes I I and I2 and the respective exhaustpipes `lf3 and Il'. Also it willbeapparent'that when the valves 9 and I0 are adjusted to connect the conduits 'I and 8 with the 'respective air inlet conduits III andv I 2", 4vcompressed air will be delivered to the respective receivers andvwill act as a piston on the surface ofv the sewage in the receivers to thereby discharge the same throughtheir respective outlets- 5;.:and 6'. Backward .flow ofsewage inthe conduit'A 35 'is `prevented* by means of suitablev check valves withgthe conduit 1 of the other receiver.

provided in the inlet conduits 3 and 4 as indicated at 33 and 34.

The position of the pistons in the valves 9 and I may be controlled by means of three-Way valves I and I6 respectively associated with the receivers I and 2. The valves I5 and I6 may be `of any suitable construction, usually embodying a movable element which is adapted to be moved betweentwo operative positions incident to the rocking of arms I1 and I8, which are respectively connected to float or like means within the receivers. One suitable float means may consist of an upper bell I9 secured to a rod 20 which'is mounted for sliding movement through the cover of the sewage receiver, suitable means being provided for preventing leakage of air out of the receiver through the passageway for the rod 2D. Another and downwardly located bell 2| in inverted position is connected to the upper bell I9. The lower bell 2| constitutes a receptacle which is normally lled with sewage so that the combined weight of the bell structure and the sewage .in Vthe lower bell is operative to move the rod 20 and arm I1 downwardly when the level of sewage in the receiver I is lowered to a suicient extent. When the level of sewage in the receiver rises, it ultimately reaches the upper bell I9 and of sewage reaches a predetermined height, to move the rod 20 and arm I1 upwardly to accordingly shift the movable element of the valve I5 When the level of sewage in the receiver I is at a predetermined height, substantially as represented in the receiver I, the valve I5 will be so adjusted as to cause compressed air to ow througha bleeder connection 22 from the piston valve 9 through the valve I5 and upwardly through a conduit 23 to one end of the piston valve so as to shift the piston therein to open the connection between the air inlet II and the conduit 1. Compressed air then ilows downwardlythrough the conduit 1 and into the receiver ito thereby effect ydischarge of the receiver I.

When the discharging operation is completed, the valve I5 is, adjusted as above described to cause compressed air to flow through the bleeder 22, through the valve I5 and upwardly through the conduit 24 to the other end of the piston valve 9 so as to effect shifting of the piston to close the connection between the air inlet I I and conduit 1 and to establish a relief connection between the outlet or exhaust I3 and said conduit 1. Sewage may then iiow into the receiver I, the air being displaced from the receiver through the conduit 1, valve 9 and exhaust I3.

. The operation of the receiver No. 2 is substantially identical with that above described in respect of receiver I.

In the absence of some means for preventing simultaneous discharge of the receivers, such discharge could occur. For reasons already indicated, it is preferable that such simultaneous discharge be prevented. For this purpose there is provided means for closing a valve-in the air diaphragm valve 25 is of more or less conventional construction and is so arranged that when air under pressure is delivered to the chamber on one side of the diaphragm, the valve 25 will be closed. 'Ihus when compressed air is being delivered through the conduit 1 to the receiver I, compressed air is also being delivered through the connection 26 to the diaphragm valve 25. The valve 25 is thereby closed to prevent delivery of compressed air to the receiver 2 so long as compressed air is beingl delivered to receiver I to effect discharge of the latter.

Assuming that air is being delivered through the conduit 1 to the receiver I and also through the connection26 to the valve 25 to close the latter, that condition will be maintained until the level of sewage in receiver I is lowered and valve I5 is adjusted to actuate piston valve 9 so as to stop the flow of compressed air to the receiver I. When that happens, the conduit 1 is vconnected to` the Iatmosphere through the exhaust I3 and air pressure in the connection 2E and diaphragm chamber of the valve 25 also released so that compressed air may ow through the conduit I2 to the Valve I0, which then will determine whether or not air will be permitted to flow into the receiver 2.

In the event that compressed air is being delivered to receiver 2, and receiver I becomes lled with sewage to such an extent that the Valves I5 and 9'are actuatedto start the delivery of air to receiver No. I, it will -be seen that the supply of air to receiver -2 Will be cut off by closing of the valve 25. This condition will then continue until discharging of `the receiver I is completed, whereupon discharging of the receiver 2 will be resumed. During such an interval in which receiver 2 is inoperative, sewage will not be permitted to enter receiver 2, due to the fact that the conduit 8 is closed by the piston valve I0 from the exhaust line I4. This, however, is not objectionable inasmuch as it ordinarily takes but a matter of around 30 seconds to discharge the other receiver, whereupon resumption of the discharge of the rst receiver is effected. During that short period in which sewage may not enter either of the receivers, it will be collected, usually in a catch basin or even permitted to back up in the piping leading `to the receivers. It will be understood that ordinarily the receivers are disposed at a considerably lower level than the remainder of the sewer system, so that there is considerable extent of `piping in which sewage may collect for the indicated short interval without creating any sort of hazard. However, even lthat situation may 'be overcome, if desired, by providing suitable fbypass connecting, inthe described arrangement, the conduit 8 .with the exhaust I4, such by-pass being controlled by a diaphragm valve which would be opened by air pressure emanating from the conduit 1. For practical purposes such a pneumatically controlled by-pass is not, however, required.

In some instances it may be preferable to substitute for the diaphragm valve 25, a solenoid or other electrically -or otherwise controlled valve which may in turn be controlled by a pressure inlet conduit II or I2, controlled by the presence of air pressure in the conduit of the other receiver.

In this instance a diaphragm valve 25 is illustrated in the air inlet pipe I2 of the receiver 2.

`Saiddiaphragm valve has a conduit 26 connecting` the chamber on one side of the diaphragm The of sewage receivers, means connected .to'said receivers for delivering sewage thereto, outlet conduitseXtending from said receivers, separate conduits for supplying airunder pressure to said receivers to thereby effect discharge of sewage therefrom, valve means in eachy of said conduits controlled -by the liquid level in the respective receivers, said valve means being operative to control the passage of air through said conduits into the respective receivers, and a normally open air pressure actuated valve in one of said air supply conduits and connected to the other of said air supply conduits so as to be closed vby compressed air from said other conduit when air is admitted thereinto by said liquid level controlled Valve.

2. In apparatus of the class described, a pair of sewage receivers, means connected to said receivers for delivering sewage thereto, outlet conduits extending from said receivers, separate conduits for supplying air under pressure to saidreceivers to thereby effect discharge of sewage therefrom, valve means in each of said conduits controlled by the'liquid level in the respective receivers, said valve means being roperative to con-Y trol the passage of air through said conduitsinto the respective receivers, and a normally open air pressure actuated valve in one of said air supply conduits ahead of the liquid level controlled valve therein, said air pressure actuated valve lbeing connected to the other air supply conduit intermediate -the liquid level controlled valve therein 'and the receiver to which said other conduit leads,

whereby said air pressure actuated valve is adapted to be closed lby compressed air from said other conduit when air is admitted thereinto .by its liquid level controlled valve.

3. In apparatus of the class described, a pair of sewage receivers, means connected to said receivers for delivering sewage thereto, outlet conduits extending from said receivers, separate conduits for supplying air under pressure to said receivers to thereby effect discharge of sewage therefrom, valve means in each of said conduits controlled -by the liquid level in the respective receivers for controlling the passage of airwthrough said conduits into the respective receivers, a nor- -mally open auxiliary valve in one of said air supply conduits and means for closing said auxiliary valve when the liquid level .controlled valve in the other conduit; is opened.

EMIL J CIABA'I'IARI. 

